Timing chain longevity on 4.0 V6???

[gdk771]

My Ranger currently has around 178,000 miles on it. I was thinking of replacing the timing chain as preventative maintenance but heard from a fellow ranger owner that he has 350,000 miles on his original timing chain. Can anyone tell me on average how long the timing chain on 4.0 V6 engines lasts? Should I worry about replacing it? I am not hearing any noise from the timing chain housing, just worried that it might stretch and skip a tooth. I know you can’t make blanket statements depending on how much maintenance the engine received over its life but I guess my question is should I replace or just not worry about it? I know these trucks have some sort of timing chain tensioner so this may be one reason they tend to last longer. Is there any way to check if you take the cover off by the “slack” in the chain?

 

[kevinsranger]

My Ranger currently has around 178,000 miles on it. I was thinking of replacing the timing chain as preventative maintenance but heard from a fellow ranger owner that he has 350,000 miles on his original timing chain. Can anyone tell me on average how long the timing chain on 4.0 V6 engines lasts? Should I worry about replacing it? I am not hearing any noise from the timing chain housing, just worried that it might stretch and skip a tooth. I know you can’t make blanket statements depending on how much maintenance the engine received over its life but I guess my question is should I replace or just not worry about it? I know these trucks have some sort of timing chain tensioner so this may be one reason they tend to last longer. Is there any way to check if you take the cover off by the “slack” in the chain?

mine has 300,000 miles on it, and as far as i know the timing chain is original!!!! and she runs and sounds great

 

[Big Jim M]

If that 96 has a distributor you can tell slack by watching the dist rotor movement while moving the crankshaft by hand back and forth A tight chain will cause the rotor to move WITH the crank movement.
Big JIm

 

[martin]

The 4 liter v6 does not have a distributor. Many guys on here have over 300k on their motors, if it's not creating a problem leave well alone.

 

[Daniel_187]

don't want to hijack but if the Timing chain goes its not a big deal right? I have heard horror stories of this happening

 

[Big Jim M]

Yes it is

don't want to hijack but if the Timing chain goes its not a big deal right? I have heard horror stories of this happening

If the timing chain does go it can be terrible! The 4.0 is an interference engine.. Meaning the pistons CAN hit the valves. If the mechanical valve timing changes, the valves can be depressed while the pistons are at TDC.. This is really bad.
The older generation of engines had weaker timing gears and chains as well as stronger valve springs which tended to streach the chains.
Our more modern timing gears and chains combined with weaker valve springs and chain tensioners have been a huge improvement in the timing systems.
Big JIm

 

[jhammel85]

don't want to hijack but if the Timing chain goes its not a big deal right? I have heard horror stories of this happening

I believe its a non interference engine. so if it goes, it'll leave you stranded but no bent valves.